Coccidia Vaccine Challenge and Exogenous Enzyme Supplementation in Broiler Chicken 2—Effect on Apparent Ileal Nutrient and Energy Digestibility and Intestinal Morphology 7 and 14 Days Post-Challenge

The efficiency with which the nutrients and energy in any diet are digested, absorbed, and utilized depends on several factors, with the health status of the bird’s gastrointestinal tract playing an important role. The protozoan parasite Eimeria has been reported to significantly reduce the performance of birds because of poor absorption of nutrients in the small intestine. In this study, the effect of Eimeria sp. challenge and exogenous enzyme supplementation on performance and nutrient digestibility in broilers fed corn-soybean meal- or wheat-corn–SBM-based diets was examined. During the first 7 days post-challenge (days 14–21), in birds fed the corn–soybean-meal-based diets, the coccidia vaccine challenge (CVC) resulted in lower BWG and feed efficiency, while birds on the enzyme-supplemented diets had higher BWG compared to birds on diets without enzyme supplementation. However, the CVC birds fed the wheat–corn–soybean-meal-based diets performed better (BWG and feed efficiency) compared to the unchallenged birds during the recovery phase (days 21–28). Findings from this study showed that the effect of CVC on broiler chickens’ performance during the recovery phase may be influenced by diet type.